Later that morning, Dr.

Chen returned with a hospital social worker and a specialist in medical toxicology.

They had contacted the appropriate public-health and law-enforcement personnel about the reported home exposure.

They explained that no one should enter the service closet without proper training and that any investigation would need clear records of who had accessed the system.

The toxicologist, Dr.

Elena Ruiz, asked Kenneth whether the children had ever been better away from home.

“The cottage,” he answered.